Brake for a wire reel

ABSTRACT

A brake for a wire reel comprises a brake arm including a wire guide and a brake shoe pivotably mounted to a base. The brake shoe establishes initial contact with the reel in its normal position and applies a negligible brake force thereto. Wire from the reel is fed under the wire guide. A removal force or tension applied to this wire moves the brake shoe away from contact with the reel to allow free rotation thereof. Release of the tension causes the brake shoe to return to the initial contact position whereupon subsequent rotation of the reel wedges the shoe into a braking contact position to stop the rotation. The brake applies a braking force in only one direction of rotation and will operate when the reel is mounted for rotation about either a horizontal or vertical axis.

United States Patent [191 Starace BRAKE FOR A WIRE REEL [75] Inventor:Jeremia Patrick Starace, Denville,

[73] Assignee: Bell Telephone Laboratories Incorporated, Murray Hill,NJ.

[22] Filed: Nov. 6, 1972 [21] Appl. No.: 304,336

[52] US. Cl. 242/156, 242/7543 [51] Int. Cl B65h 59/04 [58] Field ofSearch, 242/156, 156.1, 156.2,

[5 6] References Cited UNlTED STATES PATENTS 518,425 4/1894 Parker242/1562 UX 3,l0l,9l2 8/1963 Bartlett 242/1562 X FOREIGN PATENTS ORAPPLICATIONS 26,195 0/1897 Great Britain 242/1562 PrimaryExaminer-Stanley N. Gilreath Attorney, Agent, or Firm A. D. Hooper 5 7ABSTRACT A brake for a wire reel comprises a brake arm including a wireguide and a brake shoe pivotably mounted to a base. The brake shoeestablishes initial contact with the reel in its normal position andapplies a negligible brake force thereto. Wire from the reel is fedunder the wire guide. A removal force or tension applied to this wiremoves the brake shoe away from contact with the reel to allow freerotation thereof. Release of the tension causes the brake shoe to returnto the initial contact position whereupon subsequent rotation of thereel wedges the shoe into a braking contact position to stop therotation. The brake applies a braking force in only one direction ofrotation and will operate when the reel is mounted for rotation abouteither a horizontal or vertical axis.

1 Claim, 2 Drawing Figures BRAKE FOR A WIRE REEL BACKGROUND OF THEINVENTION l. Field of the Invention This invention relates to wirehandling apparatus and more particularly to a brake for controlling theremoval of wire from a reel.

2. Description of the Prior Art Telephone central offices use wire formaking crossconnections on the main distributing frame and similarapplications. Reels of wire are rotatably mounted to the main frame,floor, or other appropriate support means and wire is removed therefromby pulling on the end of the wire causing the reel to rotate and unwindthe wire thereon. In order to prevent wire overrun and consequententanglement and waste of wire, braking means must be provided on thewire reel for stopping the rotation thereof when the pulling or removalforce is removed from the wire.

Various types of brakes exist for controlling the payout or unwinding ofwire from the reel. One of these is a drag brake or constant frictionbrake which applies a constant braking force to the reel which must beovercome by the wire in order to remove wire from the reel. The constantdrag force applied by such brakes is difficult to adjust satisfactorilybecause the drag must be high enough to prevent excessive wire overrunand yet low enough to allow removal by reasonable pulling force. Anotherdisadvantage is that such brakes tend to wear out relatively quicklybecause of the constant drag force applied thereby.

Another commonly used wire reel brake utilizes a brake arm having a wireguide at the end thereof through which wire from the reel is fed. Thebrake arm is pivoted about an axis parallel to the axis of the reel andthe weight of the arm is selected to pivot a brake shoe into contactwith the periphery of the reel flange when the tension or removal forceis released from the wire. One disadvantage of such a brake is theuneven or jerky braking action exhibited thereby during the removal ofrelatively long segments of wire. Any momentary release of tension inthe wire causes the brake to apply a relatively hard braking force whichtends to jerk the wire from the installers hands. Another disadvantageis that such a brake will not function when the reel is mounted forrotation about a vertical axis because the weight of the pivoted brakearm is not applied in the proper direction to pivot the brake shoe intocontact with the periphery of the flange. Still another disadvantage ofsuch a brake, as well as the drag brake previously discussed, is thatthe braking action is applied regardless of the direction of rotation ofthe reel. Thus, the rewinding of wire onto the reel requires that thebraking force be overcome.

Accordingly, it is an object of this invention to improve brakes forwire reels, to provide for easy removal of the wire from the reels, andsmooth application of the braking force.

Another objective is to provide a brake which can be utilized with wirereels having either horizontal or vertical axes of rotation.

Still another object is to provide a brake which applies a braking forceto the reel in only one direction of rotation.

SUMMARY OF THE INVENTION The foregoing objects and others are achievedin accordance with the invention by a brake comprising a brake armincluding a wire guide and a brake shoe on the end thereof. The brakearm is mounted between the flanges of the wire reel for rotation aboutan axis perpendicular to the axis of the reel so that the brake shoemakes an initial contact with the reel along a relatively small area andhence applies a negligible braking force in this initial contactposition. Wire being removed from the reel is fed beneath the wireguide. When a tension or removal force is applied to the wire, the brakeshoe is removed from contact with the reel to allow free rotationthereof. When the tension is removed, the brake arm pivots to return thebrake shoe to the initial contact position with the reel. The subsequentrotation of the reel then wedges the shoe downward in full contact withthe flange thereby providing a significant braking force to stop therotation. Rotation of the reel in the opposite direction lifts the brakeshoe out of its braking contact position into the initial contactposition to allow rewinding of wire onto the reel. Because the brake isapplied by the rotation of the reel rather than by the weight of a brakearm, the brake operates when the reel is mounted for rotation abouteither a vertical or horizontal axis.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fullycomprehended from the following detailed description and accompanyingdrawing in which:

FIG. 1 is a perspective view of a brake in accordance with thisinvention mounted for utilization with a wire reel; and

FIG. 2 is a perspective view of the brake utilized in FIG. 1.

DETAILED DESCRIPTION FIG. 1 shows a wire reel 2 having wire 4 woundthereon and rotatably mounted on a shaft 6 to a support arm 8. Supportarm 8 is mounted to a base 10 which can comprise a frame or otherappropriate mounting arrangement. Wire reel 2 includes two generallycircular flanges 12 and 14 for preventing wire 4 from spilling from theedges of the reel 2. The inner or opposing surfaces or faces of flanges12 and 14 are generally planar smooth surfaces. In accordance with thisinvention, a brake 20 is utilized for arresting the rotation of reel 2and thereby controlling the winding or unwinding of wire 4 on reel 2. Asshown more fully in FIG. 2, brake 20 comprises a base 22 having a brakearm 24 pivotally mounted thereto by pin or shaft 26. Arm 24 has a sloton cutout 28 along the top edge thereof in which a generallyspool-shaped wire guide 30 is mounted. On the end of arm 24 is mounted agenerally disc-shaped brake shoe 32 which can comprise a variety ofwell-known friction materials.

Brake 20 is mounted with pin 26 substantially perpendicular to shaft 6of reel 2. In the illustrative embodiment, arm 24 is positioned betweenflanges I2 and 14 so that the face 32b of brake shoe 32 opposes theinside surface 14a of flange 14. For reasons to become apparentsubsequently, brake 20 is mounted on the side of center line 34 on whichthe rotation of reel 2 for wire removal as indicated by arrow 36 has acomponent directed into the base 22 of brake 20. In the illustrativeembodiment of HO. 1, brake is mounted to the left of vertical centerline 34 as viewed along shaft 6 in the direction of support 8 so thatflange 14 has a velocity or-rotation component at the point of contactwith shoe 32 which is directed vertically downwardly into base 22.

Wire being removed from reel 2 is fed underneath guide 30 and can betaken in a plurality of directions as indicated by arrows 38 and 40.When a tension or removal force is applied to wire 4, the verticalcomponent of this tension causes arm 24 to rotate about pin 26 and liftshoe 32 from contact with the inner face 14a of flange 14. Thus, reel 2is free to rotate and unwind wire 4 in response to the tension thereon.When the tension on wire 4 is removed, arm 24 rotates under its ownweight until the bottom portion of shoe 32 generally indicated by thenumber 32a establishes initial contact with the inner surface 14a offlange 14. At this point, face 32b of shoe 32 is not flush or parallelwith the face of flange l4, i.e., the axis 46 of shoe 32 is notperpendicular to face 14a, and only a small or negligible braking forceis applied by the relatively small contact area 32a. The verticalcomponent of force generated by any subsequent rotation of reel 2 in thedirection of arrow 36 forces arm 24 downward because of the frictionalcontact between face 14a and area 32a until face 32b of shoe 32 iswedged into a braking contact position substantially flush with face 14aof flange 14 and thereby applies a relatively large braking force to thereel. The transition from the negligible or relatively small brakingforce in the initial contact position to the large braking force in thebraking contact position is smooth because the application of thebraking force is controlled by the rotation of the reel rather than bythe weight of brake arm 24. Brake 20 operates as a disc brake on theface 14a of flange l4 and accordingly is much more efiicient thanpresently used brakes which apply the braking force to the flangeperiphery. When a tension or removal force is reapplied to wire 4, arm24 again is pivoted upward to remove shoe 32 from the braking contactposition and thereby again allowfree rotation of the reel.

lf reel 2 is rotated in the opposite or rewind direction, i.e., oppositeto the rotation indicated by arrow 36, the vertical force componentexerted on shoe 32 by the rotation of flange 14 is directed upwardly andthus shoe 32 never becomes wedged in the braking contact positionpreviously discussed but remains in the initial contact position.Accordingly, brake 20 offers a negligible braking force to the rewindingof wire onto reel 2. This is a significant advantage over existingbrakes which operate in both directions of rotation.

The actual amount of braking force applied to flange 14 can be adjustedby slightly shifting the mounting position of brake 20 with respect tothe flange. This is accomplished by shifting the position of themounting bolt or screw 42 in mounting slot 44 to move shoe 32 closer toor further away from flange 14. If brake 20 is shifted toward flange l4,shoe 32 will initially contact flange 14 along a smaller area ofcontact, i.e., the angle between axis 46 and the perpendicular to face14a will be larger, and the subsequent wedging of shoe 32 against flange14 will develop higher normal forces and hence higher braking forces. Onthe other hand, movement of brake 20 away from flange 14 reduces thebraking force by reducing the normal forces developed by the wedgingaction.

Brake 20 operates even when reel 2 is mounted horizontally, i.e.,mounted for rotation about a vertical shaft, as long as brake arm 24 isdirected downward with shoe 32 above the flange with which it makescontact. The center of gravity of arm 24 is located so that even whenbrake 20 is mounted in the vertical position, i.e., base 22 is mountedagainst a vertical surface with arm 24 directed downward, arm 24 tendsto rotate under its own weight toward base 22 until axis 46 of shoe 32is substantially perpendicular to the face of flange 14. In other words,arm 24 tends to rotate toward base 22 until face 32b of shoe 32 is flushwith face 14a of flange 14. However, as previously discussed, contactbetween area 32a and face 14a of flange 14 occurs before this amount ofrotation is achieved and the braking action is subsequently applied bythe continued rotation of reel 2. Operation with reel 2 orientedhorizontally clearly cannot be accomplished by brakes which areactivated solely by the weight of an arm which is pivoted about an axisparallel to the axis of the reel.

The foregoing discussion has been directed toward an application of thebrake where a braking force is desired in only one direction ofrotation. lf bidirectional braking is desired, two of the describedbrakes could be utilized. One brake could be placed on each side ofvertical center line 34 and braking in both directions of rotation couldbe provided. Alternatively, brake arm 24 could readily be modified toinclude two fingers or flanges onwhich are mounted brake shoes adaptedfor contacting the reel flange on respective sides of vertical centerline 34. A single wire guide could be utilized to rotate the brake armin response to a tension in the wire. The brake shoes on the respectivesides of center line 34 can provide braking in respective directions ofrotation.

While the invention has been described with reference to a specificembodiment thereof, it is to be un derstood that various modificationsmight be made thereto without departing from the spirit and scope of theinvention.

What is claimed is:

1. A brake for a wire reel mounted for rotation for winding andunwinding of wire thereon and having at .least one flange for holdingsaid wire thereon comprismeans for mountingsaid base with respect tosaid flange so that only said first edge portion of said shoe initiallycontacts said flange and so that said flange has a component ofrotational movement directed toward said base during said unwinding ofsaid wire from said reel which applies a force to said first edgeportion of said shoe to pivot said arm toward said base and wedge saidshoe into increased contact with said flange to apply said braking forcethereto; and

means including a wire guide on said arm responsive to a force unwindingsaid wire from said reel for pivoting said arm away from said base andremoving said shoe from contact with said flange to allow free rotationof said reel.

1. A brake for a wire reel mounted for rotation for winding andunwinding of wire thereon and having at least one flange for holdingsaid wire thereon comprising, in combination: a base; a brake armpivotably mounted on said base and having the center of gravity thereoflocated to cause said arm to rotate toward said base; a brake shoemounted on one end of said arm and adapted to apply a braking force tosaid flange, said shoe having a first edge portion adjacent said base;means for mounting said base with respect to said flange so that onlysaid first edge portion of said shoe initially contacts said flange andso that said flange has a component of rotational movement directedtoward said base during said unwinding of said wire from said reel whichapplies a force to said first edge portion of said shoe to pivot saidarm toward said base and wedge said shoe into increased contact withsaid flange to apply said braking force thereto; and means including awire guide on said arm responsive to a force unwinding said wire fromsaid reel for pivoting said arm away from said base and removing saidshoe from contact with said flange to allow free rotation of said reel.